The primary objective of the proposed investigation is to determine the functional relationship between loudness discomfort level (LDL), speech discrimination, type of Hearing impairment and their interaction with hearing aid amplification. During the past grant year we have established a reliable method for obtaining the LDL, validated the LDL as a measurement made primarily on a loudness basis and explored the possible relationship of the LDL to the aural reflex. During the proposed grant period we wish to determine the LDL for speech and more complex stimuli and extend the results to include various individuals with hearing impairment, divided on the basis of the site of lesion, audiometric configuration and presence of partial or complete loudness recruitment (or its absence). Furthermore we propose to study the relationship between LDL and the aural reflex at supra-threshold levels with the aid of a revised system for obtaining the reflex and a PDP-11 computer system for the precise quantification of various pertinent reflex parameters. Finally experiments are suggested for relating the LDL to speech discrimination ability especially in groups with sensorineural hearing loss.